1, all parts of the human body skin, oral cavity and external genital mucosa and other parts of the body appear irregular white patches of different sizes, single or multiple, white patches area gradually expand, the number increases. The white patches are all white, but the degree of pigment loss can be different, and can be light white, milky white, cloudy white and porcelain white. In rare cases, the white spots will appear to shrink or disappear on their own. 2, generally speaking, the white spots and normal skin are clearly demarcated, but if the white spots are in progress, the edges can also be blurred, and some can appear around the white spots as a diffusion halo of color between the normal skin and the white spots. The hair in the white spots can be white, normal or black and white, and the efficacy is relatively poor for those with white hair, and the hair can turn black after the white spots disappear. Generally speaking, the surface of the white spots is smooth, without scales or crusts, and the sensory and secretory functions are normal. But there are a few patients feel itchy at the white spot, individual is very itchy, this situation can be seen in the development and effectiveness of the white spot; there are a few vitiligo patients secretion of sweat at the white spot has a bad smell. 3, the white spot is more sensitive to sunlight or ultraviolet rays, after sun exposure can be red, burning pain, blistering, itching, and in serious cases the white spot will develop. Therefore, we advocate vitiligo patients to less sun, especially at noon or summer, when ultraviolet light is stronger to avoid. There are some photosensitive food and medicine use after the enhanced effect of ultraviolet light. How to scientifically and reasonably use ultraviolet radiation and photosensitive drugs is a question worth exploring and researching. The typical vitiligo is easy to diagnose, the early loss of incomplete, blurred edge of the damage must be distinguished from the following diseases: ( 1 ) anemic nevus: is a kind of congenital hypopigmentation, mostly at birth is present, due to hypopigmentation at the capillaries than normal scarce, rubbing the affected area when the surrounding skin is congested and the white spot remains the same, thus can be distinguished from vitiligo. ( 2 ) Non-pigmented nevus: it develops after birth or soon after birth, the damage is often distributed along the nerve segment, and it shows limited or generalized hypochromic spots, the boundary is blurred, the edge is mostly jagged, there is no pigmentation halo around it, sometimes there are light brown corn to lentil-sized freckle-like spots mixed within it, the sensation is normal, it lasts for life, it is one of the nerve nevus types. ( 3 ) lichen planus: infants and young children cases, its pale white spots often occur in the cheeks, forehead and between the eyebrows, because often scrub the surface, not easy to adhere to the scales, so it is very easy to confuse with early vitiligo, should be noted. ( 4 ) discoid lupus erythematosus: especially the discoid lupus erythematosus that occurs in the cheeks and lips, when cured often leaves a clearly defined warm pigmented patches, face like vitiligo, but this warm spot always some atrophy and capillary dilatation, sometimes can still find adhesive scales, and its under the enlarged hair follicle mouth and keratin plugs. ( 5 ) mucous membrane white spot: lip mucosa and perineal vitiligo is often easily mistaken for mucous membrane white spot. The mucous membrane leukoplakia mostly presents reticular streak-like or flaky, white keratinized damage, often itchy. In contrast, vitiligo is only depigmentation, epidermis normal, in the adjacent skin or other places can often find depigmented lesions.